Question

Evaluate the function rule for the given value. f(x) = 3^x for x = –5

Answer 1

Answer:

f(-5) = 1/ 243

Step-by-step explanation:

f(x) = 3^x

Let x=-5

f(-5) = 3^-5

Since the exponent is negative, it will move to the denominator

f(-5) = 1/3^5

f(-5) = 1/ 243

Answer 2

For this case we have the following function:

$f (x) = 3 ^ x$

We must evaluate the function for$x = -5$

So, we have:

$f (-5) = 3 ^ {-5}$

By definition of power properties it is fulfilled that:

$a ^ {- 1} = \frac {1} {a ^ 1} = \frac {1} {a}$

Thus:

$f (-5) = \frac {1} {3 ^ 5} = \frac {1} {3 * 3 * 3 * 3 * 3} = \frac {1} {243}$

Answer:

$\frac {1} {243}$